THK CANADIAN ENTOMOLOGIST. 181 



background, against which the little bugs are more clearly revealed, and 

 therefore more easily observed. The adults were kept in numbers in the 

 large aquaria, where they mated and oviposited, and the young, as soon 

 as emerged, were transferred singly to one of the small dishes, where they 

 could be observed and a more accurate record be kept of their trans- 

 formations. Every morning before going to the cffice where I earn my 

 living, the aquaria were examined, the cast skins removed, the moults 

 noted, and any other pertinent observations recorded in the books I keep 

 for the purpose. On my return from business a similar routine was gone 

 through. It is necessary to keep the aquaria, large and small, covered to 

 prevent evaporation, and also to keep the bugs from escaping, especially 

 the smaller ones. With a water surface to run upon, and food in sufficient 

 quantity, they require nothing more. A few water plants help to keep the 

 water sweet and add sightliness to the large aquaria, but they cannot be 

 successfully employed in the smaller. 



All the descriptions and figures are from balsam mounts, and this 

 perhaps may have caused some slight distortion in the form of the insect, 

 making it possibly a little broader and longer than it really is. The bugs 

 in the earlier series of slides were killed in alcohol (about 90%), washed 

 in Cologne spirits (98% alcohol), and cleared in turpentine. In the latter, 

 they were put living into carbol tur[)eutine, made by putting crystallized 

 carbolic acid into an equal part of fiue spirits of turpentine, which gives 

 excellent results, producing very clear mounts. 



One fact should be borne in mind in these life-histories, which 

 is that the conditions are largely artificial, and in all likelihood more 

 favourable than in nature, and this may contribute to an acceleration of 

 the life cycle as compared with that in natural surroundings. In the first 

 place, the food supply is regular and abundant, which is not likely to be 

 the case in Microvelia's normal haunts, for it is scarcely likely that in a 

 secluded spring they can get a single insect each a day. And in the 

 second place, the temperature is bound to be bcjth higher and more 

 constant in the confinement of a closed aquarium, and the air is more 

 heavily moisture-laden as well. A regular and abundant food supply, high 

 temperature and a moist atmosphere are all conducive to rapidity of 

 development in the Heteroptera, as may be readily verified by observing 

 how much more quickly bugs reach their moults in the hot, humid days of 

 July and August than they do in the cooler May, June, September and 

 October. 



